Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSCHEVROLET1985STEP VAN P20, 4.8 T, AUTOMATIC, 475/M40REPAIR AND DIAGNOSIS (SINGLE PAGE)ENGINE PERFORMANCETUNE-UPIGNITION SYSTEM - HEI (FEDERAL)TESTING - COMPONENT TESTSINTEGRAL IGNITION COILCHEVROLET & GMC ONLY
1985 Chevrolet Step Van P20, 4.8 T, Automatic, 475/M40
Chevrolet & GMC Only
1985 Chevrolet Step Van P20, 4.8 T, Automatic, 475/M40SECTION Chevrolet & GMC Only
- The ignition coil can be tested for shorted and open windings using an ohmmeter. Connect the ohmmeter between the positive terminal and coil frame (ground). Use the high resistance scale. The ohmmeter should indicate infinite resistance. If not, replace the coil.
- Connect the ohmmeter between the positive and negative terminals. Use the low resistance scale. The ohmmeter should indicate zero, or nearly zero. If not, replace the coil.
- Connect the ohmmeter between the negative terminal and the high voltage terminal. Use the high resistance scale. The ohmmeter should indicate less than infinite resistance. If not, replace the coil. See Fig 1.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.